The objective of the proposed research is a unified, quantitative theory of binaural interaction that is applicable to a wide variety of binaural phenomena and that is consistent with neurophysiological data on the auditory system. This research involves large amounts of both psychophysical experimentation and theoretical modeling and will include further studies of both interaural sensitivity and subjective attributes of the binaural image space. The proposed activities will capitalize on our highly-developed laboratory facilities, on modeling techniques derived from statistical communications theory, and on the systematic physiological data now available describing the peripheral transduction from acoustic waveforms to auditory-nerve firing patterns. The research is primarily concerned with the development of a mathematical description of a central processor that operates on the firing patterns as inputs and lead to psychophysical performance equivalent to that exhibited by human listeners. Most of the specific problem areas addressed by the research concern the incorporation of subjective attributes into the theory and the interaction of interaural time difference with interaural intensity difference. Included among these problem areas are sensitivity to simultaneous incremental changes in interaural time and intensity difference, the effect of reference interaural time and intensity difference on this sensitivity, the ability to discriminate between time difference and intensity difference, and the location and spatial form of the subjective image for various combinations of time difference and amplitude difference. BIBLIOGRAPHIC REFERENCES: Colburn, H.S. (1977). "Theory of Binaural Interaction Based on Auditory-Nerve Data. II. Detection of Tones in Noise," J. Acoust. Soc. Am., in press. Colburn, H.S. (1977). "Theory of Binaural Interaction Based on Auditory-nerve Data. II. Detection of Tones in Noise. Supplementary Material," Am. Inst. of Physics, 98-page document in Physics Auxiliary Publication Service (PAPS), number to be assigned; will also appear in Current Physics Microfilm.